The overall goal of this project is to utilize the polymerase chain reaction (PCR) system to identify clonal gene rearrangements in lymphoid neoplasms. The purposes include the following: detect clonality to support diagnostic work of cases, investigate and characterize lymphoid diseases, and provide sensitive methods to follow patients. Previous work in the section to identify clonal gene rearrangements has been primarily based on using Southern blot technology. However, the sensitivity is low, the methodology requires 1-2 weeks for completion, and can not be performed on DNA extracted from paraffin embedded tissue. Methods have been described using the polymerase chain reaction to amplify clonal rearrangements in both T and B cell lineages. The section has much experience performing PCR for bcl-2 in follicular lymphomas as a method to identify lymphoid clones. No PCR work has previously been done in the section with the T cell system prior to this report. T cell gene rearrangements can now be amplified from both fresh tissue and paraffin embedded tissue, including tumors such as acute lymphocytic leukemia, peripheral T cell lymphoma, mycosis fungoides, gamma delta lymphomas, subcutaneous T cell lymphomas, and lymphocytic and large cell lymphomas. A high resolution system using denaturing gradient gel electrophoresis has been adapted to follow the unique gene rearrangement for each patient's tumor. B cell immunoglobulin gene rearrangements can be amplified and this is being used to study the lymphocyte predominant form of Hodgkin's disease. This work provides the basis to do PCR in situ on paraffin tissue sections to identify specific cell types involved.